Judging from your picture, it looks like you're including clad coins as "treasure" in your 5 to 1 ratio. But if you were counting only GOLD as being "treasure", then .... it appears that others here are saying the ratios would be more like 100 to 1. That is .... if you're talking turfed parks. And I can think of parks where the ratio would be more like 1000 to 1.
So if gold rings are your agenda, then why oh why oh why are you hunting junky turf, to begin with ? Why not just hunt locations where the ratios aren't quite so punishing ? Simply go to swimming beaches. Not junky blighted parks.
And if you have no swim lakes or beaches near you, then there are types-of land -hunting where the ratios aren't quite so punishing. Eg.: Sports fields that are devoid of any picnicking eating/drinking. Eg.: soccer fields, football field sidelines (where people lay their stuff along the goal posts before going out to play , etc...). Other land locations = sand volleyball courts, mud-wrestle pits, ski-lift lines (@ summer thaw), etc.....
Because the moment you have any sort of eating, BBQ'ing, drinking, etc.... is the moment you can add foil (for the food wrap), tabs (for the drinks), and can nuggets (for the BBQ melted residue).
So the "trick" to finding gold rings is not to "dig junk till your arms fall off". Instead, the trick is: Location location location.[/quote
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Tom, I'm counting ALL locations I detect, not just parks which make up only about 20% of the sites I hunt. I also hunt our local freshwater beaches in cooler weather when the crowds are gone, old home sites, sports fields, volleyball courts (I hunted one yesterday that had already been cleaned out by another detectorist who must hit it every morning), old farms, and just about anywhere that people have been in the past. While my focus is on gold, that's certainly not the only reason I've been actively enjoying this hobby for the past 49 years. If it were, I'd have quit long ago. I love digging relics, coins (even pennies), and silver jewelry too. Finding those other interesting and often valuable items keeps me motivated to get out and detect every day. You must realize that I live in rural central Texas where the temperature has been around 100 degrees for the past several weeks so there are no saltwater beaches or ski-lifts in my area. ha. I really don't mind digging metal trash because I know that pretty soon, I'm going to find something good so I just keep at it and have fun.
Attached is a photo of a 1935 lady's gold and sterling class ring that I found in March (excuse the blurry picture as my old camera isn't what it used to be) of this year. I found it 7" down on an old house lot in Brownwood. The house was torn down in the 1970s and apparently no one had hunted it until I got permission.
~Texas Jay